Ionic liquids (ILs) are molten organic salts composed of organic cations and inorganic/organic anions with low melting points (≤100° C.). These solvents have garnered much attention due to their low vapor pressure at ambient temperatures, high thermal stability, wide electrochemical window, and multiple solvation capabilities.
The analysis of deoxyribonucleic acid (DNA) plays a central role in a variety of applications ranging from the determination of microbial diversity in environmental samples, identifying pathogens in food, monitoring the levels of cell free nucleic acids in cancer prognosis (liquid biopsies), bioprospecting, and phylogenetic studies. Techniques such as polymerase chain reaction (PCR) and DNA sequencing enable the analysis of extremely small quantities of DNA. However, the reliability and reproducibility of these methods largely depends on the quality of the sample. Complex environmental and biological samples often contain compounds such as humic acids, proteins, or lipids that can inhibit PCR amplification or DNA sequencing reactions. In these circumstances, a proper sample preparation technique is necessary to purify and preconcentrate DNA for accurate and reproducible analysis.
Various sample preparation techniques have been developed for DNA purification including phenol-chloroform alkaline extraction, cesium chloride-based density gradient ultracentrifugation, and solid phase extraction (SPE) methods. Although useful in many cases, these conventional DNA purification approaches often involve large sample volumes, the use of organic solvents, time-consuming and laborious centrifugation steps, or multiple sample transfer steps that increase the risk of contamination. DNA extraction based on commercial SPE kits reduces the volume of organic solvent consumed as well as the time required for analysis, but the cost per sample remains high and the number of extractions that can be performed is limited. In some cases, the yield and purity of DNA obtained using different commercial extraction kits can be highly variable. Consequently, new methods that address the deficiencies of existing DNA sample preparation techniques are particularly desirable.